scholarly journals Field evaluation of specificity and sensitivity of a standard SARS-CoV-2 antigen rapid diagnostic test: A prospective study at a teaching hospital in Northern Ghana

Author(s):  
Alhassan Abdul-Mumin ◽  
Abdulai Abubakari ◽  
Faith Agbozo ◽  
Abass Abdul-Karim ◽  
Benjamin Demah Nuertey ◽  
...  

Background: The testing capacity for SARS-CoV-2 in Africa is rather limited. Antigen-detection rapid diagnostic tests (Ag-RDTs) are a cheap and rapid alternative to reverse transcriptase-polymerase chain reaction (RT-PCR) tests, but there is little data about their performance under real life conditions in tropical countries. Objective: To evaluate the performance of a standard Ag-RDT in a population of a major hospital in northern Ghana. Methods: Prospective, cross-sectional, blinded verification of the performance of the SD Biosensor Standard Q SARS-CoV-2 Ag-RDT under real life conditions in 135 symptomatic patients and 58 contacts of RT-PCR positives at Tamale Teaching Hospital in February 2021. Nasopharyngeal samples were taken under standard conditions and tested against RT-PCR in the hospital laboratory. Results: 193 participants (median age 35 years, 109 male) were included into the study for which both RT-PCR test and Ag-RDT results were available. A total of 42 (22%) were RT-PCR-positive. Of the 42 RT-PCR-positives, 27 were Ag-RDT positive, resulting in a sensitivity of 64% (95% CI 49-79). Sensitivity among symptomatic patients was 58% (95% CI 38-78). 123 were identified Ag-RDT negatives of the 151 RT-PCR negatives, resulting in a specificity of 81% (95% CI 75-87). Conclusions: SARS-CoV-2 Ag-RDTs appear to have a rather low sensitivity and particularly a low specificity under real life conditions in Africa. The role of existing Ag-RDTs in countries with high-temperature climates and limited resources still needs more data and discussion.

2021 ◽  
Vol 1 (12) ◽  
pp. e0000040
Author(s):  
Alhassan Abdul-Mumin ◽  
Abdulai Abubakari ◽  
Faith Agbozo ◽  
Abass Abdul-Karim ◽  
Benjamin Demah Nuertey ◽  
...  

The testing capacity for SARS-CoV-2 in Africa is rather limited. Antigen detection rapid diagnostic tests (Ag-RDTs) are a cheap and rapid alternative to reverse transcriptase-polymerase chain reaction (RT-PCR) tests, but there is little data about their performance under real life conditions in tropical countries. The objective of this study is to evaluate the performance of a standard Ag-RDT in a population of a major hospital in northern Ghana. Prospective, cross-sectional, blinded verification of the performance of the SD Biosensor Standard Q SARS-CoV-2 Ag-RDT under real life conditions in 135 symptomatic patients and 58 contacts of RT-PCR positives at Tamale Teaching Hospital in February 2021. Nasopharyngeal samples were taken under standard conditions and tested against RT-PCR in the hospital laboratory. 193 participants (median age 35 years, 109 male) were included into the study for which both RT-PCR test and Ag-RDT results were available. A total of 42 (22%) were RT-PCR positive. Of the 42 RT-PCR positives, 27 were Ag-RDT positive, resulting in a sensitivity of 64% (95% CI 49–79). Sensitivity among symptomatic patients was 58% (95% CI 38–78). 123 were identified Ag-RDT negatives of the 151 RT-PCR negatives, resulting in a specificity of 81% (95% CI 75–87). SARS-CoV-2 Ag-RDTs appear to have a rather low sensitivity and particularly a low specificity under real life conditions in Africa. The role of existing Ag-RDTs in countries with high-temperature climates and limited resources still needs more data and discussion.


Author(s):  
Eliseo Albert ◽  
Ignacio Torres ◽  
Felipe Bueno ◽  
Dixie Huntley ◽  
Estefanía Molla ◽  
...  

AbstractWe evaluated the Panbio™ COVID-19 AG Rapid Test Device (RAD) for the diagnosis of COVID-19 in symptomatic patients attended in primary healthcare centers (n=412). Overall specificity and sensitivity of RAD was 100% and 79.6%, respectively, taking RT-PCR as the reference. SARS-CoV-2 could not be cultured from specimens yielding RT-PCR+/RAD- results.


2021 ◽  
Vol 15 (10) ◽  
pp. 3356-3358
Author(s):  
Ambreen Fatima ◽  
Nidda Yaseen ◽  
Amna Fareed ◽  
Kashif Ali Samin ◽  
Shumaela Kanwal ◽  
...  

Background and Aim: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid emergence postured significant challenges on the health system in recent years. The early detection of cases is thought to be critical in preventing this pandemic by coronavirus disease (COVID-19), especially important in the obstetrical population due to theirs numerous interactions with another parturient when hospitalized for delivery. Therefore, the present study aimed to assess the COVID antigen test performance in COVID-positive obstetrics patients. Materials and Methods: This cross-sectional study was conducted on 1296 Covid-19 asymptomatic women admitted to the Obstetrics and Gynaecology Department of Muhammad Teaching Hospital & Medical College, Peshawar and Fauji Foundation Hospital, Rawalpindi for the duration of six months from February 2021 to July 2021. Antigen-based test rapid diagnostic test (RDT) was used for screening out COVID-19 positive obstetrics patients or women through nasopharyngeal swabs. Women with negative rapid antigen test results were confirmed with RT-polymers chain reaction test of nucleic acid amplification tests (NAAT). Ethical approval and informed consent were taken from the hospital ethical committee and each individual respectively. All the known positive COVID-19 patients during admission were excluded. SPSS version 24 was used for data analysis. Results: The overall prevalence of rapid antigen-positive tested patients was 13.2% (171/1296). The prevalence of positive tested women through rapid antigen test, Nucleic Acid Amplification Test (NAAT), and RT-PCR were 27 (2.1%), 51 (3.9%), and 93 (7.2%) respectively. Of the total 1296 rapid antigen tests, 27 were positive, and the false-negative confirmed positive by NAAT was 144.Thus the sensitivity of the rapid antigen test was 15.8% and the negative predictive value was 93.7%. Of the total 298 Nucleic Acid Amplification Tested had sensitivity and negative predictive value of 89.6% and 99.06% respectively. RT-PCR was carried out on 972 patients, positive diagnosed cases were 36 while 15 were initially negative and were positive with the test was repeated. The sensitivity and negative predictive value was 71.45% and 95.8% respectively. Conclusion: Our study found that Ag-RDT plays a significant role in SARS-CoV-2 early detection in infected individuals, with high specificity and sensitivity to disease infectious stage, whether symptomatic or asymptomatic, and can be used as a decision supported tool. Early detection of COVID-19 status in women admitted for delivery could benefit neonatal protection care. Keywords: Covid-19; Rapid antigen test; RT-PCR test


Author(s):  
ANCY SEBASTIAN ◽  
ANEESHA PK ◽  
JOSHWA AREECKAL ◽  
SONIYA DAVIS

Objective: The aim of this study is to evaluate the pattern of prescription and utilization of antidepressants (ADs) for various non-psychiatric indications in department of general medicine, cardiology, surgery, gynecology, and orthopaedic of a tertiary care teaching hospital. Methods: A prospective cross-sectional unicentric drug utilization study of inpatients was carried out in a 450 bedded tertiary care hospital. The study included 200 subjects admitted for both psychiatric and non-psychiatric illness. Pediatric patients and those with a length of stay <48 h were excluded from the study. Results: Prescriptions of 200 patients were studied in which 55% were males and 45% were females. The most widely prescribed drug is alprazolam comprising 50% of the total drug consumption and is followed by clonazepam (19.5%), amitriptyline (13.5%), diazepam (9.5%), escitalopram (3.5%), lorazepam (3%), and zolpidem (0.5%). About 36% of the drugs were prescribed in the general medicine department, and 27.5% of the prescriptions were from the cardiology department. Prescriptions from surgery, orthopedics, and gynecology were 16%, 11.5%, and 9% of the total, respectively. Conclusion: ADs were found to be potentially useful for non-psychiatric indications such as peripheral and diabetic neuropathy, gastroenterological conditions, and urological conditions. No benefit was observed in insomnia and musculoskeletal conditions except for fibromyalgia. ADs were also found to improve the treatment outcome and quality of life of patients having comorbid psychiatric conditions being treated for non-psychiatric disorders.


2020 ◽  
Author(s):  
Marta Fernández-González ◽  
Vanesa Agulló ◽  
Alba de la Rica ◽  
Ana Infante ◽  
Mar Carvajal ◽  
...  

AbstractBackgroundData on the performance of saliva specimens for diagnosing COVID-19 in ambulatory patients are scarce and inconsistent. We assessed saliva-based specimens for detecting SARS-CoV-2 by RT-PCR in the community setting and compared three different collection methods.MethodProspective study conducted in three primary care centres. RT-PCR was performed in paired nasopharyngeal swabs (NPS) and saliva samples collected from outpatients with a broad clinical spectrum of illness. To assess differences in collection methods, saliva specimens were obtained in a different way in each of the participating centres: supervised collection (SVC), oropharyngeal washing (OPW) and self-collection (SC).ResultsNPS and saliva pairs of samples from 577 patients (median age 39 years, 44% men, 42% asymptomatic) were collected and tested, and 120 (20.8%) gave positive results. The overall agreement with NPS and kappa coefficients (KƘ) for SVC, OPW and SC were 95% (Ƙ=0.85), 93.4% (Ƙ=0.76), and 93.3% (Ƙ=0.76), respectively. The sensitivity (95% CI) of the saliva specimens varied from 86% (72.6-93.7) for SVC to 66.7% (50.4-80) for SC samples. The sensitivity was higher in samples with lower cycle threshold (Ct) values. The best performance of RT-PCR was observed for SVC, with sensitivity (95% CI) for Ct values ≤32 of 97% (82.5-99.8) in symptomatic, and 88.9% (50.7-99.4) in asymptomatic individuals.ConclusionsSaliva is an acceptable specimen for the detection of SARS-CoV-2 in the community setting. Specimens collected under supervision perform comparably to NPS and can effectively identify individuals with higher risk of transmission in real life conditions.


2021 ◽  
Author(s):  
Naomi Fujita-Rohwerder ◽  
Lars Beckmann ◽  
Yvonne Zens ◽  
Arpana Verma

Objective: To systematically assess the diagnostic accuracy of rapid point-of-care tests for diagnosis of current SARS-CoV-2 infections in children under real-life conditions. Study design: Multiple bibliographic databases including MEDLINE and Embase, clinical trial registries and further information sources were systematically searched for literature (last bibliographic search: May 7, 2021). Diagnostic cross-sectional or cohort studies that included paediatric study participants and evaluated rapid point-of care tests for diagnosing current SARS-CoV-2 infections against RT-PCR as the reference standard were eligible for inclusion. QUADAS-2 was used to assess the risk of bias and the applicability of the included studies. Bivariate meta-analyses with random effects were performed. Variability was assessed by subgroup analyses. Results: We included 17 studies with a total of 6355 paediatric study participants. All included studies compared antigen tests against RT-PCR. Only one study was at low risk of bias. The pooled overall diagnostic sensitivity and specificity in paediatric populations was 64.2% (95% CI: 57.4%-70.5%) and 99.1% (95% CI: 98.2%-99.5%), respectively. In symptomatic children, the pooled diagnostic sensitivity was 71.8% (95% CI: 63.6%-78.8%) and the pooled diagnostic specificity was 98.7% (95% CI: 96.6%-99.5%). The pooled diagnostic sensitivity in asymptomatic children was 56.2% (95% CI: 47.6%-64.4%) and the pooled diagnostic specificity was 98.6% (95% CI: 97.3%-99.3%). Conclusions: Performance of current antigen tests under real-life conditions varies broadly. Policymakers should especially be aware of the low diagnostic sensitivity of current antigen tests. Results should be interpreted with caution since risk of bias was predominantly judged as unclear due to poor reporting. Study Registration: CRD42021236313 (PROSPERO).


2020 ◽  
Author(s):  
Mar Masiá ◽  
Marta Fernández-González ◽  
Manuel Sánchez ◽  
Mar Carvajal ◽  
José Alberto García ◽  
...  

ABSTRACTBackgroundPerformance of point-of-care tests in clinical practice remains undetermined. We aimed to evaluate the performance of the nasopharyngeal Panbio COVID-19 antigen Rapid Test Device in real-life conditions in different clinical scenarios.MethodProspective study conducted in three primary care centers (PCC) and an emergency department. The antigen test was performed at point-of-care in nasopharyngeal and nasal swabs, and in saliva. Positive and negative percent agreement (PPA, NPA) were calculated with the RT-PCR assay as reference standard.ResultsOf 913 patients included, 296 (32.3%) were asymptomatic and 690 (75.6%) came from the PCC. Nasopharyngeal swabs were collected from 913, nasal swabs from 659, and saliva from 611 patients. RT-PCR was positive in 196 (21.5%) nasopharyngeal samples (NPS). Overall PPA (95% CI) in NPS was 60.5% (53.3-67.4), and it was lower in nasal swabs (44.7%) and saliva (23.1%). Test performance in NPS was largely dependent on the cycle threshold (Ct) in RT-PCR, with PPA>90% for Ct≤25 and ≥80% for Ct<30. In symptomatic patients, the PPA was 95% for Ct≤25; ≥85% for Ct<30, and 89% for the symptom triad of fever, cough and malaise. Performance was also dependent on age, with PPA of 100% in symptomatic patients >50 years with Ct<25. In asymptomatic patients, the PPA was 86% for Ct<25. In all cases, NPA was 100%.ConclusionThe nasopharyngeal Panbio COVID-19 antigen test performed at point-of-care is highly sensitive in symptomatic patients, particularly with Ct<30 and older age. The test was useful to identify asymptomatic patients with lower Ct values and therefore with contagious risk.Key pointsThe nasopharyngeal Panbio-COVID-19 antigen test performed in real-life conditions at point-of-care is highly sensitive in symptomatic patients, particularly with Ct<30 and older age. The test is useful to identify asymptomatic patients with lower Ct values and therefore with contagious risk.


2021 ◽  
Author(s):  
IRERI THIRION-ROMERO ◽  
SELENE GUERRERO-ZUNIGA ◽  
ALEXANDRA ARIAS-MENDOZA ◽  
DORA PATRICIA CORNEJO-JUAREZ ◽  
PATRICIA MEZA-MENESES ◽  
...  

BACKGROUND Point-of-care rapid tests to identify SARS-CoV-2 can be of great help because, in principle, they allow decisions to be made at the site of care for treatment, or for the separation of cohorts avoiding cross-infection, especially in emergency situations. METHODS A cross sectional study in adults requesting care in Emergency Rooms (ER), or the outpatient clinics of referral hospitals for COVID-19, to define the diagnostic characteristics of a rapid antigen test for SARS-CoV-2 (the Abbott PanbioTM) having as a gold standard the RT-PCR for SARS-CoV-2. Health personnel in a routine situation within an active pandemic in several cities of Mexico performed the tests. RESULTS A total of 1,069 participants with a mean age of 47 years (SD 16 years), 47% with a self-reported comorbidity, and an overall prevalence of a positive RT-PCR test of 45%, were recruited from eight hospitals in Mexico. Overall sensitivity of the Panbio test was 54.4% (95%CI 51-57) with a positive likelihood ratio of 35.7, a negative likelihood ratio of 0.46 and a Receiver-Operating Characteristics curve area of 0.77. Positivity for the rapid test depended strongly on an estimate of the viral load (Cycle threshold of RT-PCR, Ct), and the days of symptoms. With a Ct 25, sensitivity of the rapid test was 0.82 (95%CI, 0.76-0.87). For patients during the first week of symptoms sensitivity was 69.6% (95%CI 66-73). On the other hand, specificity of the rapid test was above 97.8% in all groups. CONCLUSIONS The PanbioTM rapid antigen test for SARS-CoV-2 has a good specificity, but due to low and heterogeneous sensitivity in real life, a negative test in a person with suggestive symptoms at a time of community transmission of SARS-CoV-2 requires confirmation with RT-PCR, and after the first week of symptoms, sensitivity decreases considerably.


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